In connecting two pairs of two leads, generally end portions of the leads are removed of their outer covering material to expose copper wires of single or multi-core, and they are twisted around each other and then wrapped around with insulating tape to prevent electricity from leaking out or a person from touching to be electrically shocked.
However, this common way of connecting leads has several drawbacks.
1. Manually twisted connecting portions are easily separated from each other.
2. Insulating tape covering a connected portion becomes hard to break or looses adhesiveness for a certain period of use so that naked wires may be exposed to cause danger of shortcircuit.
3. Manual connecting takes time and a connected portion looks bad.